Sickle Cell Anemia (Sickle Cell Disease)
What is sickle cell anemia?
Sickle cell anemia is a form of the inherited blood disorder, sickle cell disease. Sickle cell anemia affects your red blood cells, turning them from round flexible discs into stiff and sticky sickled cells. Sickled cells keep red blood cells from doing their job, which is carrying oxygen throughout your body. Sickled cells also don’t live as long as normal red blood cells. As a result, you don’t have enough healthy red blood cells and you develop anemia, the condition that gives sickle cell anemia its name.
In the past, babies born with sickle cell anemia rarely lived to be adults. Now, thanks to early detection and new treatments, about half of all people who have sickle cell anemia live into their 50s. People who have sickle cell anemia still face potentially life-threatening medical complications. However, healthcare providers have treatments that reduce the risk of complications and ease symptoms when they happen. (Unfortunately, there are many places in the world where people still don’t have access to effective medical treatment for sickle cell anemia.)
Who is affected by sickle cell anemia?
Sickle cell anemia is rare in the United States, affecting about around 100,000 people. It mostly affects people whose ancestry links back to parts of the world where many people have malaria and carry a gene that provides partial protection against anemia. This gene also causes sickle cell anemia. In the United States, sickle cell anemia affects many people who are Black. It may also affect people from southern European, Middle Eastern or Asian Indian ancestry.
How does sickle cell anemia affect people?
Babies born with sickle cell anemia may not have symptoms for several months. When they do, symptoms include extreme tiredness or fussiness from anemia, painfully swollen hands and feet, and jaundice. Babies may also have spleen damage that affects their immune system and increases their risk for bacterial infections. As people with sickle cell anemia grow older, they may develop different and more serious medical problems that happen when organ tissues don’t receive enough oxygen. People with sickle cell anemia are at increased risk for stroke and lung, kidney, spleen and liver damage.
Symptoms and Causes
What causes sickle cell anemia?
People with sickle cell anemia inherit the disease from their biological parents. In sickle cell anemia, the gene that helps make normal red blood cells mutates, or changes. People who inherit the mutated hemoglobin protein gene from both biological parents have sickle cell anemia. People who inherit the mutated gene from one biological parent have the sickle cell trait.
How does this mutation affect normal red blood cells?
Normal red blood cells contain hemoglobin. Hemoglobin is a protein and the main part of red blood cells. When the hemoglobin gene mutates, it creates sickled cells that can’t navigate the network of blood vessels that carry oxygen, nutrients and hormones throughout your body. Here’s why:
- Normal hemoglobin is soluble, meaning it dissolves in fluid. Abnormal hemoglobin isn’t as soluble and ends up forming solid clumps in your red blood cells.
- Red blood cells need to be flexible to squeeze and slide their way through narrow blood vessels. Red blood cells carrying abnormal solid hemoglobin can’t do that. Instead, blood cells with abnormal hemoglobin end up blocking blood vessels and blood flow.
- Normal red blood cells live about 120 days. Sickled cells self-destruct within 10 to 20 days. Normally, your bone marrow makes enough red blood cells to replace dying cells. When cells die earlier than usual, your bone marrow becomes like a factory struggling to match supply with demand. When the bone marrow factory can’t keep up, you don’t have enough red blood cells.
What are the signs and symptoms of medical conditions linked to sickle cell anemia?
Sickle cell anemia symptoms typically start when babies are 5 to 6 months old. As they grow older, most people with sickle cell anemia have increased risk for developing new medical conditions. Some of these conditions are life-threatening. But by learning about conditions and symptoms, people with sickle cell anemia can seek help at the first sign of trouble so healthcare providers can treat the condition.
Vaso-inclusive crisis (VOC)
Healthcare providers may call this condition acute pain crisis. VOC, or acute pain crises, is the most common reason why people with sickle cell anemia go to the emergency room or need to spend time in the hospital. Symptoms include:
- Sudden intense pain.
- Pain can be sharp or stabbing.
- VOC may affect any part of your body, but typically affects your abdomen, lower back, arms and legs.
Living with VOC is one of the more difficult aspects of having sickle cell anemia. Among other symptoms and complications, people who have sickle cell anemia may feel depressed or anxious because they’re dealing with certain stigmas associated with the condition.
Stigma and sickle cell anemia
Healthcare providers sometimes call VOC the invisible illness because people who are having a pain crisis many times don’t have symptoms other than sudden excruciating pain that’s only eased with opioid painkillers.
Studies show sickle cell anemia carries a stigma linked to people’s need for opioid painkillers to manage VOC. Other studies show people who are members of racial minorities receive less pain medication and have to wait longer for pain medication than people who are white. Combined, these stigmas are a one-two-punch, as sickle cell anemia commonly affects people who are Black or Hispanic.
Acute chest syndrome (ACS)
Acute chest syndrome is the most common complication of sickle cell anemia. It’s also the most common cause of death and the second most common cause of hospital admission. It happens when sickled cells clump and clog blood vessels in your lungs. Symptoms include:
- Sudden chest pain.
- Trouble breathing.
People who have sickle cell anemia may have mild, moderate or severe forms of anemia. Symptoms include:
- Having skin color that’s more pale than usual.
- Fatigue. This is feeling too tired to manage daily activities.
- Trouble breathing.
In addition to these symptoms, babies with anemia may be unusually fussy or irritable. Children may not grow as fast as other children their age or may enter puberty later than children their age.
Anyone who has sickle cell anemia is at risk for stroke, including babies. Approximately 11% of people with sickle cell anemia have strokes by age 20, and 24% have strokes by age 45. Here is information on stroke symptoms:
- Severe headache.
- Sudden weakness on one side of your or your child’s body.
- Change in alertness.
- Trouble speaking.
- Trouble seeing.
- Trouble walking.
This happens when sickled cells become stuck in your spleen, forcing your spleen to get larger. Splenic sequestration often causes acute anemia. Symptoms include:
- Pain in your upper left belly (abdomen).
- Sometimes, children’s enlarged spleens are visible or can be felt through their skin.
People with sickle cell anemia have an increased risk for infections caused by Streptococcus pneumoniae, Haemophilus influenzae and non-Typhi Salmonella species. Symptoms include:
- Trouble breathing.
- Pain in bones.
About 35% of all people who are assigned male at birth (AMAB) who have sickle cell anemia develop priapism, or painful erections, that last four hours or more.
About 2% of people with sickle cell anemia develop leg ulcers, usually after age 10. Leg ulcers are more common in people AMAB and people age 65 and older. Symptoms are painful sores that don’t heal. People often develop these sores on their ankles.
Pulmonary hypertension (PH)
About 6% to 11% of people with sickle cell anemia develop pulmonary hypertension (PH). Symptoms include:
- Racing pulse.
- Fainting (passing out) or dizziness.
- Feeling short of breath during exercise or activity and difficulty breathing when at rest.
Chronic kidney disease
About 30% of people with sickle cell anemia have chronic kidney disease. Symptoms include:
- A need to pee (urinate) more often.
- Loss of appetite.
- Swollen hands, feet and ankles.
- Shortness of breath.
- Blood in pee (hematuria) or pee that looks foamy.
- Puffy eyes.
- Dry and itchy skin (pruritus).
- Trouble concentrating.
- Trouble sleeping.
- Nausea or vomiting.
- Muscle cramps.
- High blood pressure (hypertension).
- Skin color that’s noticeably darker than usual.
Sickled cells can cause detached retinas by blocking blood vessels in your retinas. Common symptoms include:
- Seeing flashes of light.
- Seeing many floaters — flecks, threads, dark spots and squiggly lines that drift across your vision. (Seeing a few here and there is normal and not cause for alarm.)
- Darkening of your peripheral vision (side vision).
- Darkening or shadows covering part of your vision.
- Darkening or shadow covering part of your vision.
Diagnosis and Tests
How do healthcare providers diagnose sickle cell anemia?
Healthcare providers diagnose sickle cell anemia by taking blood samples. They may use a technique called hemoglobin electrophoresis or high-performance liquid chromatography. This test identifies and measures different types of hemoglobin in red blood cells, including the abnormal hemoglobin that causes sickle cell anemia. (Starting in 2007, all babies born in the United States have sickle cell anemia tests right after they’re born. Early diagnosis and treatment are why fewer babies and young children born in the United States die of sickle cell anemia.)
What are the chances that my child will be born with sickle cell anemia?
That depends on whether you and/or your partner inherited sickle cell anemia or have sickle cell trait. Sickle cell trait isn’t a disease. People with sickle cell trait have a mixture of normal and abnormal hemoglobin in their red blood cells. They have enough normal hemoglobin in their red blood cells to prevent the cells from sickling. However, they do have an increased risk of having children with sickle cell anemia.
If you and your partner both have sickle cell trait, your child has a 25% chance of being born with sickle cell anemia. If only one of you has sickle cell trait, your child won’t be born with sickle cell anemia, but there’s a 50% chance that your child will be born with sickle cell trait. Studies estimated about 1 to 3 million people in the United States carry sickle cell trait, including about 8% to 10% of people who are Black.
Healthcare providers can diagnose sickle cell anemia before your baby is born. They do this by taking a sample of the biological mother’s amniotic fluid or tissue from the biological mother’s placenta. Then, they examine the samples for signs of the sickle hemoglobin gene that causes the condition.
Management and Treatment
Can healthcare providers cure sickle cell anemia?
Right now, allogenic stem cell transplantation is the only way healthcare providers can cure sickle cell anemia and other forms of sickle cell disease. Healthcare providers typically recommend transplantation for people who have severe complications such as stroke, acute chest syndrome or recurring VOC/acute pain crises.
How do healthcare providers treat sickle cell anemia?
Healthcare providers typically treat sickle cell anemia with blood transfusions, antibiotics to treat infections and medications that reduce symptoms caused by sickle cell anemia complications. These medications may include hydroxyurea, voxlelotor, L-glutamine therapy and crizanlizumab.
Hydroxyurea (brand names Droxia®, Hydrea ®, Siklos®, Mylocel®)
Hydroxyurea (pronounced “hye drox ee ure ee a”) is an anticancer drug now used to treat sickle cell anemia. In 2017, the U.S. Food and Drug Administration (FDA) approved hydroxyurea as sickle cell anemia treatment for children age 2 and older, as well as adults. Studies show hydroxyurea:
- Cuts the number of VOC/acute pain crises by 50%.
- Decreases instances of acute chest syndrome.
- Reduces the need for blood transfusions.
- Improves anemia symptoms.
- In children, hydroxyurea eases dactylitis, which causes painful swelling.
Voxelotor (brand name Obryta®)
This medication prevents red blood cells with abnormal hemoglobin from becoming sickled cells. Voxelotor (pronounced “vox el oh tor”) may prevent some red blood cells from being destroyed faster than your bone marrow can replace them. In 2019, the FDA approved voxelotor for sickle cell disease treatment. In late 2021, the FDA approved voxelotor as treatment for children age 4 and older.
L-glutamine therapy (brand name Endari®)
L-glutamine helps reduce some of the complications linked to sickle cell anemia. Sickled cells develop over time. L-glutamine helps protect sickled cells from becoming more misshapen. In 2017, the FDA approved Endari for treatment of children age 5 and older and adults.
Crizanlizumab-tmca (brand name Adakveo®)
People with sickle cell anemia cope with sudden bouts of excruciating pain called VOC/acute pain crises. In 2019, the FDA approved crizanlizumab-tmca (pronounced “criz-l-izum-ab”) medication to treat people age 16 and older. This medication may help reduce how often VOC/acute pain crises happen.
How can I prevent sickle cell anemia?
Sickle cell anemia is an inherited disorder. You can have a blood test to find out if you have sickle cell trait that you could pass on to your children. People can have sickle cell trait without having sickle cell disease or sickle anemia.
Outlook / Prognosis
What can I expect if I have or my child has sickle cell anemia?
Sickle cell anemia is a chronic illness than can’t be cured. There are, however, medications that healthcare providers use to manage sickle cell anemia complications. In some cases, these medications can keep sickle cell anemia from getting worse. Young children may use some of these medications. As children grow up, they may be able to take medications that do more to manage sickle cell anemia complications.
What is the life expectancy for someone who has sickle cell anemia?
There was a time when babies born with sickle cell anemia rarely lived past age 5. Now, healthcare providers are able to diagnose sickle cell and begin treatment that eases symptoms and complications. People are living into their 50s with sickle cell anemia. Even so, people who have sickle cell anemia live 20 to 30 years less than people who don’t have the condition.
What’s it like to live with sickle cell anemia?
New treatments are helping people with sickle cell anemia live longer and with better quality of life. The U.S. Centers for Disease Control and Prevention (CDC) has the following suggestions for living well with sickle cell anemia:
- Find good medical care. Sickle cell anemia is complicated. Many times, managing sickle cell anemia requires a multidisciplinary team of healthcare providers who specialize in blood disorders.
- Get regular checkups. Regular health checkups with your primary provider care may head off serious medical complications. Having a relationship with your healthcare provider who understands your situation may make it easier to get help if you have an acute pain crisis.
- Pay attention to your emotional health. Unfortunately, there are stigmas associated with sickle cell anemia. Sometimes, these stigmas cause people to have depression or anxiety. Talk to your healthcare provider if you’re struggling with emotions related to feeling stigmatized. They can recommend resources to help you. More than that, they may be able to advocate for you by educating peers about sickle cell anemia complications and symptoms.
- Prevent infections. Talk to your healthcare provider about vaccinations and take steps to protect yourself from infection.
- Eat a healthy diet. Eat a balanced diet and drink eight to 10 glasses of water every day.
- Manage your environment. People who have sickle cell anemia need to maintain a balanced body temperature to avoid VOC/acute pain crises, so it’s important that you avoid getting too hot or too cold.
- Get some exercise. Regular physical activity boosts your mood and your health. But be sure to take it easy, rest when you need to and stay hydrated.
- Get support. Because sickle cell anemia is a rare disease, most people don’t understand what it’s like to live with it. Ask your healthcare provider for support group suggestions.
- Look for clinical trials. Healthcare providers and researchers are constantly testing new treatments. Joining a clinical trial may be a way to obtain new medication and treatment. Ask your healthcare provider for help finding a clinical trial.
Living with medical complications
Sickle cell anemia is a chronic illness with symptoms that change over time. For example, children and adults have to cope with pain from acute chest syndrome or VOCs. They’re at increased risk for stroke. As people grow older, they’re likely to develop new complications such as chronic lung disease and painful leg ulcers.
If you or your child has sickle cell anemia, ask your healthcare provider what you can do now and what you should expect. They’ll likely plan regular tests to monitor signs and symptoms so they can diagnose and treat complications as early as possible.
Studies show people with sickle cell anemia are constantly trying to manage pain that many times affects their quality of life. Sometimes, they have acute pain that happens when sickled cells block blood flow. This is VOC and is a medical emergency. Other people have chronic pain — pain that lasts for more than three to six months. If you have chronic pain, consider working with a pain management specialist. They can recommend different ways you can manage pain.
When should I go to the emergency room?
Sickle cell anemia may cause serious medical conditions. Go to the emergency room if you have the following symptoms:
- Extreme fatigue.
- Shortness of breath.
- Irregular heartbeat.
Symptoms of acute chest syndrome
- Fever of more than 101.3 degrees Fahrenheit (or 38.5 degrees Celsius).
- Chest pain.
Symptoms of stroke
- Sudden weakness.
- Numbness on one side of your or your child’s body.
- Trouble speaking, seeing or walking.
Painful erections that last four hours or more. This is a symptom of priapism.
A note from Cleveland Clinic
For more than a century, healthcare providers and families struggled with the heartbreaking consequences of babies born with sickle cell anemia. Few babies lived long enough to celebrate their 5th birthdays. Starting about 10 years ago, healthcare providers began making huge strides in treating sickle cells anemia. A baby born now is likely to live well into their 50s. Thanks to research, healthcare providers can treat sickle cell anemia as a chronic illness. But it’s an illness with serious, and sometimes life-threatening, medical complications. If you or your child has sickle cell anemia, you may be grateful for the past progress, but eager about the future. Researchers and healthcare providers are laser-focused on finding a cure for sickle cell anemia.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy